urn

Generate random numbers without duplicates

Description

urn works like random, except that it keeps track of each number which has been generated. When all numbers up to the maximum (set via an argument or the right inlet) have been output, the next bang which urn receives causes a bang to be sent out the right outlet.

Arguments

Name Type Opt Description
random-generator-limit int opt The number of possible values for the random number generator. If no argument is typed in, there will be only 1 possible number.
seed-value int opt A second argument is used to set a "seed" value for the random generator. If no argument is specified, the time value will be used to initialize the seed.

Messages

bang In left inlet: Sends out a previously unchosen random number from 0 to one less than the specified maximum limit.
int random-generator-limit [int]
In right inlet: Clears the list of already chosen numbers, and specifies the number of possible values for the random number generator. The random numbers will range from 0 to one less than this maximum limit.
  (inlet1) random-generator-limit [int]
In right inlet: Clears the list of already chosen numbers, and specifies the number of possible values for the random number generator. The random numbers will range from 0 to one less than this maximum limit.
clear In left inlet: Clears the list of already chosen numbers.
seed random-generator-seed [int]
In left inlet: The word seed, followed by a number, provides a "seed" value for the random generator, which causes a specific (reproducible) sequence of pseudo-random numbers to occur. The number 0 uses the time elapsed since system startup (an unpredictable value) as the seed, ensuring an unpredictable sequence of numbers. This unpredictable seed is used by default when the urn object is created. However, once all numbers have been chosen, the sequence will repeat. Therefore, in order to achieve a non-repeating sequence of numbers, you will need to send the urn object the seed 0 message each time you send it the clear message.

Information for box attributes common to all objects

Output

bang: Out right outlet: When all numbers in the current range have been generated, urn sends a bang out the right outlet instead of a number out the left outlet.
int: Out left outlet: If there are numbers within the current range that have not been sent out since the last clear message was received, urn generates a random number between 0 and one less than the maximum.

Examples

Choose random numbers without repeating a choice

See Also

Name Description
decide Choose randomly between on and off (1 and 0)
deferlow Defer the execution of a message (always)
drunk Output random numbers in a moving range
random Generate a random number